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Reviews Categories | Filters, Audio: (DSP and others) | Idiom Press SCAF-1 Help

Reviews Summary for Idiom Press SCAF-1
Idiom Press SCAF-1 Reviews: 91 Average rating: 4.7/5 MSRP: $89.95
Description: The new SCAF-1 filter from Idiom Press makes your radio listener friendly, whether you are an SSB or CW operator. Using a modern but little known technology called SCAF filtering, the SCAF-1 is an active audio low pass filter offering user control of the filter cut-off frequency, yielding a stunning 96dB per octave roll-off of signals above the cut off frequency, and no white noise. It is the perfect partner for your crystal or mechanical filters. And, unlike most audio filters, there is absolutely NO ringing.
Product is in production.
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KM6AXC Rating: 3/5 Jul 15, 2016 07:15 Send this review to a friend
Really Powers in the CW signal  Time owned: 0 to 3 months
I am a 72 year old newbie at this stuff so I thought I'd pass on this tidbit for other non-tech guys. First, the product probably deserves a "great" rating but I as yet don't know enough about what I am doing to fully appreciate the product:) All the reviews below should give you enough info on how it performs, I'll just give you a hint on how to improve the instructions/device hook up. The instructions say in part ".......cut one end off and then solder on the connector that is correct for your radio". NAW!! Just go to Radio Shack, buy a stereo cable and an adaptor that takes your stereo plug and magically transforms it into an RCA plug. Also, for some reason (my lack of knowledge perhaps??) if you have headphones on when you hit various switches, be aware that a loud "pop" will occur and may hurt your ears. For me, I have learned to turn the receiver gain down and then push other buttons. But a small thing for the signal improvement the product produces. If you know how to eliminate the pop, please let me know??
KA8DDT Rating: 5/5 May 30, 2016 22:15 Send this review to a friend
Outstanding audio filter!!!  Time owned: 0 to 3 months
I just assembled my new SCAF-1 audio filter from and itís just as exceptional as the company and reviewers said it would be in sorting out weak signals in big pileups.

I got back into ham radio and CW two years ago with a new radio and antenna, but the internal 500 Hz audio filter I bought for my new radio and my old stand-alone audio filter simply werenít up to the task.

Online, I found the reviews touting the SCAF-1 audio filter. But unfortunately, the SCAF-1ís manufacturer, Idiom Press, had gone out of business and, which acquired Idiom, had sold all of its SCAF-1 units.

But ordered up a new batch of SCAF-1 units, which went on sale in May.

The filters come in two versions: a kit you can build ($108.95) or an assembled and tested unit ($148.95).

I bought the kit, which arrived quickly, and assembled it in two evenings. Iím a bit rusty on electronic kit assembly, so the company sent me full color .pdf to replace the black and white photocopied instructions that came with the kit. The color photos were a big help. The instructions coordinate perfectly with the component numbering printed on the circuit board.

I got bogged for a bit wiring the rear panel jacks, but after carefully re-reading the instructions, I connected everything perfectly and the unit fired up on the first try.

What I love about this unit is its ability to filter out unwanted radio signals. Unlike my old external audio filter, this one eliminates headphone hiss and makes ham radio and CW more fun.

The companyís website says the SCAF-1 works just as effectively on voice. has a demonstration video on its website.

NG0K Rating: 4/5 Mar 13, 2016 08:11 Send this review to a friend
Very Useful  Time owned: more than 12 months
I built one a several years ago then stowed it away when I got an FT-950. I recently put it back into service on the R75 receiver and it works great. While designed mostly for CW, it works great to clarify signals on SSB and even on AM. I ding it a point on ergonomics. I recommend a front mounted headphone jack. I added a headphone/speaker toggle in the front, which was an easy mod.
AF2DX Rating: 4/5 May 17, 2014 15:23 Send this review to a friend
It does the job but...........  Time owned: more than 12 months
Does not come close to the NE-QRP CLUB CW FILTER.
I just did a side by side comparison with the Idiom press SCAF filter and the NE-SCAF club filter
The Idiom press does a good job but the NE/SCAF club kit filter comes way ahead and the price for the kit is about 1/2.
I think the latest kit that the New England put out was using a different chip and gave it a bit less hiss but i'm happy with mine
AD9DX Rating: 5/5 Aug 13, 2013 17:06 Send this review to a friend
Neat little toy  Time owned: more than 12 months
I bought my Scaf second hand but unused at a hamfest. While I did not "need" it, I am a bit of a filter nut trying to get that last bit of an edge out of my system. I have plenty of filtering options with my K3 and its optional 200hz roofing filter but what the Scaf does is take a bit of the edge off. It also in some situations gives signals a bit of "pop" bringing it out from the noise floor.

Has this filter gotten me any new ones that I wouldn't have otherwise? Absolutely not! What the filter does do is make the time on the air more enjoyable. And less fatiguing, something the K3 desperately needs.
AD4C2006 Rating: 5/5 Jul 10, 2013 18:26 Send this review to a friend
One great filter  Time owned: 0 to 3 months
For years I have heard about how good this SCAF-1 was but never had a chance to own one.
Recently a guy on put one for sale for a decent price already assembled and made my mind,tonight I have it conected to the headphones connector of my new FTDX-5000MP and after listening for an hour I think there is only one word to express my impression: WOW !!
Its amazing how well this filter works, either on CW or SSB the filtering is very effective, I have been able to notch very strong stations just 200 or 300 Hz away from weak ones on CW and just 1.5 to 1.8 Kz away on SSB, its just like having a very well design DSP in your hands, so now with the help of sharp roofing filters and this very selective audio filter I have a very good sharp receiver. I don't even need to use the Contour/Audio filter control of the 5K.
I have to congratulate the designer and builder of this SCAF-1 because this circuit is very effective.
It not only narrow the audio passband but also cuts down the band noise to the point that look like we have the powerful effective "DNR" from the 5K.
I also tested with the K3 and it works terrific with that radio as well.
Its a keeper as a great accesory for the station no matter how old or new be your radio.

K6WHP Rating: 2/5 May 1, 2013 11:27 Send this review to a friend
Unit So-So; Service Terrible   Time owned: 0 to 3 months
I am compelled to weigh in with a less-than-sunny evaluation of this product. I had written a previous review (removed by based upon my experiences with the Idiom Press people and their failure to not only not deliver their product BUT TO REFUSE TO ACKNOWLEDGE MY ORDER AND RESPOND TO E-MAILS AND PHONE CALLS OVER A SIX-WEEK PERIOD. (I was not alone in travails like these; another ham had similar contemporaneous problems and likewise cancelled his order.) I can understand the previous review being removed because it was not about the product per se.

Anyway, aside from the fact that I did not have my order honored and ultimately cancelled with them, I bore the actual product no malice. In fact, because I was able to pick up one at a swap meet -- one requiring repair work, by the way -- I want to now write of my experiences and offer caveats to anyone contemplating purchasing the product or the kit. Here goes:

Firstly, the unit I got at the swap did not work. Attempts to find a manual were fruitless until a fellow ham graciously sent me a copy of his. Upon commencing the repair work I noted that there were radical differences between the manual and the actual unit I had on hand. While the board may have been accurate per the manual, the front switch was not. My unit had a DPDT with six tabs and the manual had nine tabs. The wiring on the unit I had bore only the remotest resemblance to the wiring in the documentation.

Please note that the instructions were published in 2006 and there was an addendum of corrections outlining a means of modifying the LM386 circuitry so it would perform better. (I think circa 2008) It was a very complex series of "four instructions up from the bottom change x to y" steps and occurred to me that perhaps the owner should have REWRITTEN the original to reflect the changes and tied them more tightly to board/kit revisions.

When I finally got my unit working, I was pleased -- BUT NOT IMPRESSED -- with its performance. The circuit is merely a low pass filter comprised of the two SCAF chips driven by a 555 timer. It ain't rocket science. Frankly, the NEScaf kit by the New England QRP club ( and the HI-PER-MITE ( offer products with as much promise, are very well supported, and are much more reasonably priced than the Idiom Press SCAF-1 unit.

Finally, previous "I bought mine several years ago, built it, and love it" reviews might be nice and fuzzy and heartwarming but you will be spending anywhere from $95 to $130 for one of these things and, if so, you had better be prepared for

(1) At least six weeks of being ignored after your order is taken.
(2) The prospect of a kit whose instructions are ambiguous and possibly out-of-date.
(3) A pathetic record when it comes to support and service.

The 2 is for the performance of the unit. Were I to rate the overall experience with Idiom Press with respect to the SCAF-1, it would be zero.

Color me not impressed.
WB0FDJ Rating: 5/5 Apr 16, 2013 12:09 Send this review to a friend
Does a great job  Time owned: more than 12 months
Purchased as an assembled unit several years ago. I am currently using this on an old TT Argonaut 509. Completely eliminates the high frequency hiss and white noise, making copy much less fatiguing. Signals which were buried become copyable. For older rigs that lack the newer features this is a very useful accessory and I highly recommend it. It's small enough it can sit on top of my FT-817 easily. Simple to use.

Back when I ordered mine I waited a long time for delivery, then sent a polite email inquiring about my order. I received a reply that basically said, "we are behind, sorry you had to wait so we will only charge you the kit price". I'm still impressed by that.
KG4LLQ Rating: 5/5 Feb 18, 2013 11:20 Send this review to a friend
Very Good Alternative to IF CW Filter  Time owned: more than 12 months
I built & have used the SCAF-1 since 2002. It is an excellent alternative to IF CW filters optioned in low-end HF transceivers. I use mine exclusively with an IC-718 and find I can "weed out" most any adjacent signal. If compared to a 500 Hz IF CW filter I recently installed in my IC-703; I'd say the SCAF-1 is an excellent buy. It's fun to build and performs as stated.
VR2ZXP Rating: 5/5 May 4, 2012 03:04 Send this review to a friend
All things perfect!!  Time owned: 0 to 3 months
1) Very easy to assembly. 2 days should be enough.

2) Components are in normal grade but much better than those China brand kits.

3) Cosmetic is very good. Looks smart and much better than those MFJ products.

4) It's really helpful to reduce the noise in SSB & CW mode. The roll off is very sharp. I can't found out the difference between using the most narrow bandwidth of this filter to listen the morse code in CW with 600Hz IF filter or in SSB mode with 2.4kHz IF filter.

5) When switching on the power, a very loud "Po" noise will be heard but it is acceptable on this kind of low cost product.

General speaking, if you want to pay higher cost to buy DSP filter like Timewave, I suggest you to save the money and try this little box first.
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